Bayern Munich’s schedule has been simply punishing this season.
Throw in the fact that many of the club’s key players are starters for their country’s national team and you have a perfect storm for injuries and fatigue. Coach Hansi Flick has to make critical decisions on who to rest, for how long and when. The good news is that modern sport science gives him a wealth of information to assist him in making those choices.
Long gone are the days when you noted a player’s minutes and simply asked him if he was “good to go.” Using systems widely discussed by Ralf Rangnick and installed at Bayern during Nico Kovac’s regime the coaching team can effectively assess which players are suffering the most from fatigue and how they respond to various types of work and rest.
It’s not just about being tired any more. Modern sport recovery science divides the topic into three categories or types of fatigue, each requiring their own assessment and treatment:
- Central nervous system fatigue
- Muscle or peripheral fatigue
- Psychological fatigue
There are a number of ways to measure fatigue, but many of them are not suitable for in season use. Some of the tools that the Bayern staff are using to measure the fatigue of the players include the following:
- Self-report: Players will be asked to fill out an electronic questionnaire detailing their subjective assessment of how they are feeling mentally and physically each day. These are assessed individually and tracked over time. There are a number of well-studied self-assessment tools available for this purpose. However, there are always issues of players not willing to be entirely frank about reporting their status or players becoming hyper-vigilant when asked to self-monitor too closely.
- Heart rate monitoring: For many teams, due to budgetary concerns this is the best tool available. Changes in heart rate patterns during exercise, during exercise recovery or even resting heart rate in the morning can tell the coaching staff a great deal about how fatigue is impacting player performance.
- Neuromuscular response: A series of not overly taxing jump tests can be performed to measure both CNS and peripheral fatigue, as well as measure injury susceptibility.
- Joint range of motion and flexibility: Studies have shown that changes in the range of motion of the knee and adductor muscles are both good indicators of fatigue levels particularly in soccer players.
- Biochemical/hormonal/immunological changes: This is the fun stuff only the rich teams get to play with. Daily testing of saliva and blood offers teams a treasure trove of exactly how players are responding to the athletic load being placed on their bodies and minds. Teams will track creatine kinase, IL 6 cytokines, c-reative protein, uric acid, cortisol and testosterone, salivary immunoglobulin A and a number of other biological markers to allow them to adjust both training and playing loads very precisely for each player.
Interestingly most pro teams only use blood and saliva testing to measure these biochemical changes and eschew urine tests due to the negative association players have with urine testing arising from their traditional use to detect performance enhancing drug use.
A balancing act
So, when Hansi Flick and his staff gather to discuss who will be rested, who will play, and for how long, they are assisted by a mountain of data, charts and subjective information provided to them by their players.
Then the magic happens. They assess the importance of the match, the qualities, position and status of each player (is a 15% fatigued Thomas Müller better than his potential well-rested replacement?), recent and planned and training patterns, the periodization plan for the player, the qualities of the opponent both individually and systematically, and all of the same factors for upcoming matches as well, and finally decide who to play and who to rest.